VECSELs typically comprise a first end mirror and an active region formed in a layer sequence, and a second end mirror arranged separated from the layer sequence and forming an external cavity of the laser. In standard setups the external cavity is composed of macroscopic optical elements, which are very bulky and need involved adjustment. By realizing the external optical components from a wafer and bonding this wafer to the wafer carrying the layer sequence, which is typically a GaAs wafer, it is possible to manufacture many thousands of micro-VECSELs in parallel and test them directly on the wafer like VCSELs (vertical cavity surface emitting laser diodes).
Known optically-pumped VECSELs need separated mounting and alignment of the pump lasers to the resonator or cavity of the VECSEL. This requires time-consuming production and bulky modules.
US 20100014547 A1 discloses a device for longitudinal pumping of a solid state laser medium. This device comprises several pump laser diodes which are mounted on side faces of a cooling device of the laser medium. The pump radiation emitted by the laser diodes is reflected by several parabolic mirrors toward one of the end faces of the solid state laser medium. In this device the several parabolic mirrors have to be precisely aligned in order to achieve the desired intensity distribution of the pump radiation at the entrance of the solid state laser medium.